Thanks for the suggestion, but I was going to start pushing in a different direction with the way I'd recommend using parameters. In the plugins we're building internally we're now using lambdas a lot, and finding that to be a good pattern. I'll be publishing some helper classes based on that very soon.
Also, there's no reason for this to go into the base class. The same thing would work perfectly well as a subclass, which would be a better solution since it wouldn't bloat everyone's parameter objects with unused arrays. Since few people would use this, and many plugins have thousands of parameters, putting it in the base class would probably be a bad move!